This invention relates to electrostatographic process equipment and, more particularly, to a brush apparatus for cleaning toner and other particles from the image-bearing surfaces of such equipment.
In electrostatographic process equipment, desired toned images are produced or reproduced, through a repeatable cycle, on selected receivers by employing electrostatic charges and toner on an insulated image-bearing surface. A typical cycle includes the steps of (1) using electrostatic charges in some manner to form a latent image on the image-bearing surface; (2) develping this image with particles of toner; (3) transferring the toned image to a receiver; and (4) cleaning residual toner and other particles from the image-bearing surface in preparation for repeating the cycle.
The quality of images obtained by repeating these steps depends significantly on the ability to clean the image-bearing surface before it is reused. The cleaning step is, therefore, important and has led to the development of may cleaning methods and apparatus. One such method and apparatus utilizes a rapidly rotating fiber brush to sweep the residual toner and other particles from the image-bearing surface. In ths method and apparatus, the brush is mounted within and spaced from a housing that is typically connected to a vacuum system for transporting the brush-swept particles out of, and away from, the housing.
In order for this method of cleaning to remain effective after an initial period, the brush must itself be effectively cleaned before it recontacts and attempts to clean the image-bearing surface. This is because toner particles, removed from the image-bearing surface by the brush, become entrained in the fibers.
Attempting to clean the image-bearing surface with such particle-laden fibers usually results in redeposition of some of the particles back on such surface. It also results in scumming, and in increased water and tear of the surface. Redeposition occurs because some of the toner particles in the fibers are flung by the rotating fibers against the surface, especially on the area downstream of the point where the brush contacts and cleans such surface.
Scumming is the formation, over a period of time, of an undesirable film on the image-bearing surface due to some of the particles fusing to that surface. Such fusion occurs because of a combination of reduced airflow and increased friction from the particle-laden fibers sweeping against the surface. Such particle-laden fibers, in addition, act as an abrasive, and therefore can accelerate and increase surface wear and tear. In brush cleaning, therefore, it is important to thoroughly remove toner particles from the rotating brush fibers before the fibers recontact the image-bearing surface.